Goodman GMVC960803BN Error Code E12: Redundant Relay Open
What Does Code E12 Mean?
E12 on the Goodman GMVC960803BN means the redundant gas valve relay — a secondary relay on the integrated control module that forms part of the gas valve safety circuit — is detected as open when it should be closed. With that path broken, the gas valve circuit cannot be completed and the burners will not light.
This furnace uses a dual-relay design on the gas valve circuit as a safety feature. One relay commands the valve to open during a normal heat call, while the redundant relay provides an independent backup shutoff path. The control module watches both. When the redundant relay fails open, it interrupts the series circuit and prevents the main relay from being able to energize the valve at all.
E12 is the direct counterpart of E13: E12 is the redundant relay stuck open when it should be closed, whereas E13 is that same relay stuck closed when it should be open. Because the relay is built into the integrated control module and is not a separately replaceable part, correcting E12 normally means replacing the entire control board after the diagnosis is confirmed.
What You'll Notice
- The furnace will not fire and the burners never ignite
- The 7-segment display shows E12
- The fault persists across power resets
- The inducer may complete its pre-purge, but no gas ignition follows
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Faulty redundant gas valve relay on control board | Most common | ✗ Call a pro → |
How This Is Diagnosed
A technician confirms the diagnosis by checking the state of the redundant gas valve relay on the integrated control module and ruling out related gas valve circuit faults. Because this relay is integral to the board and not separately replaceable, an open relay that cannot close is verified before the entire control module is replaced.
When to Call a Professional
This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:
- E12 is present and the control board's redundant relay must be confirmed failed before the board is replaced
- Control board replacement is required, which is a specialized repair for a qualified HVAC technician
- The fault persists after a power reset, indicating a hardware failure on the board rather than a transient
Frequently Asked Questions
What is the redundant relay?
It is a second relay on the control board that provides a backup gas-valve shutoff path as a safety feature. On E12 it is stuck open when it should be closed, breaking the gas valve circuit so the furnace cannot fire.
How is E12 different from E13?
E12 means the redundant relay is open when it should be closed, which simply prevents firing. E13 means it is stuck closed when it should be open, which is the more safety-critical failure because gas flow cannot be shut off through normal control.
✓ Verified against manufacturer service manual — March 2026